PoA - Snape knew?/Who is the real dark character in the series?

[Catlady (Rita Prince Winston)]

No: HPFGUIDX 143566

Whizbang wrote in
http://groups.yahoo.com/group/HPforGrownups/message/143527 :

<< we know that Snape is capable of Legilimency and highy skilled in
Occlumency. When he thought he was dealing with the real Moody on the
stairs, he was angry and self righteous. It was after the staring
match that Snape's attitude suddenly changed. Now we've seen this kind
of staring match before. (snip) When Sirius and Lupin engaged in a
staring match, information was exchanged mentally in what seems to be
a form of legilimency. (snip) This is what happened between Snape and
Crouch/Moody on the stairs. Up to this point, Snape has been perfectly
able to give "Moody" as good as he gets, but his attitude takes a
remarkable turn here.

Quote: GoF, ch 25
Snape was looking down at Moody, and Harry couldn't see the expression
on his face. For a moment, nobody moved or said anything. Then Snape
slowly lowered his hands.

"I merely thought," said Snape, in a voice of forced calm, "that if
Potter was wandering around after hours again ... it's an unfortunate
habit of his ... he should be stopped. For - his own safety."

"Ah, I see," said Moody softly. "Got Potter's best interests at
heart, have you?"

There was a pause. Snape and Moody were still staring at each other.
Mrs Norris gave a loud meow, still peering around Filch's legs,
looking for the source of Harry's bubble-bath smell.

"I think I will go back to bed," Snape said curtly.

"Best idea you've had all night," said Moody. >>

I just had an idea about that -- maybe it was a duel of two
Occlumenses trying to Legilimens each other without being 'read'
themselves, and maybe Crouch/Moody broke Snape's barrier, causing a
gusher of Snape memories as when Harry used the Shield (Protego!)
Charm during the Occlumency lesson in OoP. Then Snape could be scared
that the Alastor (!) has access to his memories, maybe even that the
gusher included incriminating memories that Alastor could use against
him, without Snape knowing that 'Moody' was a fake.